Bar's Leak for coolant leak

Pro - cheap
 
Con - only temporary
      - run the risk of plugging the heater core

How big is the risk of damage to the heater core?  Are there any factors that tend to make it more likely or less likely?

I've seen it happen about 1 out of every 10 times people use it. If it does happen you just need to flush the heater core.

Thanks Shawn.

I ended up deciding against using the Bar's Leak, so I can't help anyone who might be searching for results on using it.  I took the truck to the shop to see how much it would cost to fix and it turned out to be the freeze plug above the starter and only cost $77.00 parts and labor to have fixed.  It was an easy choice.